Exciton effects in carbon nanotubes

Exciton effects in quasi-one-dimensional materials such as carbon nanotubes are expected to be important due to confinement of electrons and holes. We present a simple picture of these effects based on an effective mass description of electron-hole pairs moving on the surface of a cylinder. A compilation of results for different geometries shows that the exciton binding energy follows the same dependence on diameter and chiral angle as the measured excitation energy. The exciton effects are found be substantial and produce a complete rearrangement of the absorption spectrum. (C) 2003 Elsevier Ltd. All rights reserved.